Brick

To brick a Wii is to damage the console beyond repair - as in 'A bricked Wii has all the electronic functionality of a brick'. To put it simply, fully bricked Wii consoles do absolutely nothing.
The term is often used in situations where modifying a system's firmware (without necessarily making any alterations to the machine's hardware) has caused it to become inoperable.

Types of Bricks

Semi/Partial Brick

A Semi/Partial Brick occurs when a System Menu update from the wrong region is installed on a Wii or some resources have been otherwise damaged, breaking some (but not all) of the functionality of the System Menu. Typically, games will still boot but the Settings menu will not work -- this prevents the system from healing itself with an online update. These cases can be fixed by installing a newer version of the System Menu from a disc of the correct region, or with any other tool that can modify the System Menu.

Banner Brick

A Banner Brick occurs when the user installs a channel with an invalid banner (wrong image size). With this type of brick the system will freeze after the Health and Safety screen and may display a "System Files are Corrupted" error message. This can be fixed if the Wii has previously had BootMii (as Boot2),WC24 title booting or Preloader installed, otherwise it's the hypothetical equivalent to a Full Brick.

Since boot2 is intact during a Banner Brick, any user who owns a pre Q4 2008 Wii with BootMii installed (as boot2) can access BootMii regardless of any corrupt WAD installed. From here they can access the HBC to uninstall the broken channel.

NOTE: Uninstalling the incorrect channel may lead to further damage, so users should be careful.

Alternatively, if the user has Preloader installed, they can use it to access the HBC and uninstall the broken channel.

NOTE: Uninstalling the incorrect WAD may lead to further damage, so users should be careful.

Full Brick (System Menu)

Generally speaking, a "full brick" occurs when the System Menu refuses to boot for any reason. There are two typical symptoms of a full brick:

1. The Wii displays an Opera error message instead of the “WARNING SCREEN" when the Wii boots and does not check the disc drive for a disc before displaying the error. Because of this it's impossible to fix using software unless you have BootMii installed (as boot2), or you use a Savemii Dongle with an autoboot disc.

2. The Wii displays nothing and you are presented with a black screen. Because of this it's impossible to fix using software, UNLESS you have BootMii installed (as boot2) In some cases the latter will be unable to fix this brick.

A broken Bluetooth Module will present the same symptoms, but can only be fixed by replacing the module.

Full Brick (IOS)

If the Wii NAND filesystem is corrupt, the System Menu's IOS is missing or invalid, or the System Menu executable is missing or invalid, then the system will refuse to boot and nothing will be displayed on the screen. Depending on the exact cause of failure, Preloader or BootMii/boot2 can fix (and are required to fix) this sort of brick, assuming they are installed and the system boots far enough to run them.

A broken Wifi Module will present the same symptoms, but can only be fixed by replacing the module.

Low Level Brick (LLB)

A LLB occurs when part of the boot process is corrupt -- boot1 is corrupt, or boot2 is corrupt. Since boot2 is required to be working and able load an IOS before the system can run, any errors in this process will render the system inoperable. A LLB cannot be fixed with software and requires hardware modification to be repaired.

Simply boot a recovery program the way you would any other. if you have Preloader installed, but it boots to the System Menu then try holding down reset when you turn on your Wii, after a few seconds of holding reset the Preloader menu should appear.

If you installed BootMii as boot2, then simply go to the second options screen and choose the second icon which can recover from the brick.

IOS

If you installed BootMii as part of an IOS, then you will need Preloader installed. Go to the HBC via Preloader, then select Launch BootMii from the main menu.

Using a NAND Programmer

Requires:

Soldering many wires to the Wii's motherboard

In order to use a NAND Programmer/Infectus to rewrite the flash directly you will need to know your Wii's NAND keys.

WC24 title booting

WC24 title booting can be used to fix banner bricks. The types of bricks this can fix is similar to the "recovery mode" menu. That menu can be triggered by holding down all D-Pad buttons on the GC controller plugged into slot 4, a tab inside the controller needs removed in official GC controllers. Every time the file at the boot mail entry URL installed by wc24app is updated, every Wii that already downloaded the boot mail would download again and wakeup for title booting again. The entry URLs that wc24app installs includes the consoleID, this can be used to send unique content for one Wii. If you need the boot mail content for the entry installed by wc24app to be updated to fix your bricked Wii after it already downloaded and booted with the mail, contact Yellows8 on the talk page, or send an email to yellowstar6 at gmail dot com.
To repair a Wii with WC24 title booting, the following requirements must be met:

Like the "recovery mode" menu, sysmenu IOS must be working correctly

HBC must be installed since the boot mail would boot HBC, WC24 title booting can't boot discs.

Sysmenu needs to be working without completely crashing to allow shutting down to idle/"standby" mode

Before the brick occurs, you need to run wc24app v1.1(currently from SVN or this build) on the Wii to install the boot mail entry, and to enable the WC24 title boot flag. The title boot flag is never cleared or set after file creation by Nintendo software, this flag is only cleared by Nintendo software on file creation. Nintendo announcement mail can't be intercepted and modified since that mail is RSA signed.(Modifying that mail is only possible if the sysmenu IOS has the signature check patched or has the fakesign bug, and any other IOS that run when the mail is newly downloaded/downloaded when mail is updated would need the sig patch or have the fakesign bug.)

Sending it to Nintendo

This option is the least desirable for homebrew users, as Nintendo will likely send back a different console, with your personal settings/VC account transferred and the latest updates installed.

Cause of bricks

CLEANUP

Each region has its own version of the System Menu (1-2). For example, 3.2 of the System Menu available is v. 288 (NTSC/J), v.289 (NTSC/U), v.290 (PAL). The only difference between those three versions is two different files — the main executable for the menu (a .DOL file, more or less) and an ARC archive that stores compressed versions of the HTML / image resources.

All of this is fine and good, but why put them in separately named directories? (E.g. EU/EU/GER/Setup/ScreenSave.html above)? The path name could always be the same because there are different files for each version.

If there’s a specific path that the graphics need to sit at, you’d think they’d hard-code a pathname like that into the code, right? No…

The code’s pretty hard to tease apart, but they seem to be trying to determine the system region from the setting.txt file, and then building up a pathname to load like so: sprintf(filename, “html/%s2/iplsetting.ash/%s/%s/ENG/Setup/ScreenSave.html”, region, region, region). This is so silly, because if they had hard-coded the path then the system would have booted just fine.

A full brick is caused when SYSCONF is missing, damaged, or has the "reconfiguration" flag set. This usually occurs after certain updates. The Wii would usually show the settings screen on boot to let you adjust some settings, but since it is broken, you end up with an un-bootable Wii.

A banner brick is caused when a channel with a malformed banner (icon), is installed. Due to the poor error checking of the System Menu, the system menu cant handle the corrupted banner, so it crashes and thinks that it is a file corruption.